Manufacture of seamless tubes.



F. E. SIMPKINS.

MANUFACTURE OF SEAMLESS TUBES.

APPLICATION r1120 APR. 11. 1911. RENEWED OCT. 23. 1914.

l 141,424. Patented June 1, 1915.

3 SHEETS-SHEET I.

wnn zsscs E mvzm'on F. E. SIMPKINS.

MANUFACTURE OF SEAMLESS TUBES.

APPLICATION FILED APR. 11. 1911. RENEWED OCT. 23. I914.

1 1 4 1 ,424 Patented June 1, 1915.

WITNESSES F. E. SIMPKINS.

MANUFACTURE OF SEAMLESS TUBES. LICATION FILED APR. 17, 1911. RENEWED ocTK23.1914

APP 1 1 4 1 ,424. Patentd June 1, 1915.

3 EEEEEEEEEEEE 3- FRANK E. SIMIKINS, OF YOUNGSTOWN, OHIO.

MANUFACTURE OF SEAMLESS TUBES.

Specification of Letters Patent.

Patented June 1, 1915.

Application filed April 17, 1911, Serial No. 621,654. Renewed October 23, 1914. Serial No. 868,333.

To all whom it may concern:

Be it known that I, FRANK E. SIMPKINS, a resident of Youngstown, in the county of Mahoning and State of Ohio, have invented certain new and useful Improvements in the Manufacture of Seamless Tubes, of which the following is a specification.

This application is, in part, a continuation of my application Serial No. 502,266, filed June 15, 1909.

One object of this invention is to provide for so manipulating the metal While in the roll pass in which it is pierced as to prevent slipping, and thus avoid the injurious effects of friction.

A further purpose is to secure the necessary rolling action with the least or shortest extent of rolling contact, with the active portion of the pass and the mandrel so arranged as to keep the metal free from distorting strains.

The invention contemplates gripping the metal by a kneading, surface-displacing action opposite the mandrel point, and also preferably in advance of and at the rear of the mandrel point where the resistance of the metal and its tendency to sli are greatest. This gripping and kneading toughens the metal and improves its quality without injuriously disarranging its fiber, the roll surface irregularities being of such form as to indent and knead the metal by a displacing action due to pressure as distinguished from cutting or shearing.

A further characteristic of the invention due to manipulating the metal as described is that the tube emerges from the ass only slightly larger than the mandre so that subsequent elongation to reduce the diameter, common in the art as now ractised, is avoided. The work is preferably so performed that only a relatively small amount of smooth rolling is necessary, and this is confined to the last portion of the pass for smoothing out irregularities resulting from kneading and expanding the metal, and for polishing the tube.

In practicing the invention the axes of the rolls are arranged out of parallel and in lines which cross each other, as is common in cross rolling, and the arrangement is such that the axial lines cross in the diverging portion of the pass and in advance of the point of the piercing mandrel and where the metal is firmly gripped by the surface irregularities of the rolls so that the hold is positive where the strain is greatest and slipping is positively prevented.

In the accom anying drawings, I show several forms 0 rolls for practicing the invention, Figure 1 bein a side elevation of rolls each having opposite intersectings iral grooves, and Fig. 2 is a top lan o the same. Fig. 2 is a longitudlna section of the mandrel and the portion of the metal operated upon in the roll pass, together with portions of the roll surfaces. Fig. 3 is a top plan of the rolls each formed with parallel grooves Fig. 4 is a similar view of rolls each formed with a single spiral groove. Fig. 5 is a view in top plan showing the rolls formed with dimple-like depressions. Fig. 6 is a view partly in elevation and partly in section wherein one roll element is of wheel form with its inner periphery surfaced to cooperate with a roll, and Flg. 7 is a view of the same partly in top plan and partly in section. Figs. 8 and 9 are details illustrating the depressions shown in Figs. 5, 6 and 7.

In each of the several adaptations, with the exception of that shown in Figs. 6 and 7, the opposing rolls of each set are of the same size and shape, with their spindles disposed obliquely to the roll pass and to each other to effect cross rolling and obtain the blank-feeding action, well known in the art.

In the adaptation of Figs. 1 and 2, the rolls A are of general frusto-conical form, their spindles B being disposed as described relatively to the roll pass. The ends C of the rolls at the pass inlet may be variously shaped as they have no effect in the rolling operation other than to facilitate entrance of the blank into the roll pass. As here shown, said portions C are dished or concaved so that practically no gripping or rolling action takes place in advance of the billet or blank X enterin between the irregular surfaces of the ro ls. As the purpose is to avoid friction-developing engagement between the rolls and the metal said roll ends may be variously formed to facilitate guiding or directing the blank to the active portion of the pass without acting on it.

The roll indentations or irregularities shown in Figs. 1 and 2 are in the form of opposite or crossing spiral grooves D which form relatively long and narrow diamondshaped projections E, the grooves being formed only with rounded walls and corners, abrupt edges being purposely avoided so that the gripping of the metal results in a surface displacing, pressing or kneading action, as distinguished from abruptly cutting into the surface and severing the fiber, as would be the case if the grooves were formed with sharp edges or corners. With the grooves D crossing each other as shown, the surface of the blank is subjected to a constantly changing displacement or shifting surface kneading all the while it is in contact with the grooved portions of the rolls, the relatively long and narrow projections E, in somewhat staggered relatlon as a result of the spiral grooving, accomplishing this shifting kneading in a most effective way.

Projections on the plane of the paper of the axial lines of the rolls are indicated, respectively, at a and b, Fig. 1. These lines cross each other and also intersect axial line 0 of the mandrel forwardly of the piercing point of mandrel F, as indicated at G, Fig. 2, and this intersection is referred to herein as the crossing point or point of intersection of the roll axes. Thus the metal is positively gripped when encountering the greatest resistance which latter occurs where it is first divided by the point of the mandrel. This resistance has in many instances resulted in such friction as to produce a much higher heat than that developed in the metal preparatory to the rolling operation, and such excessive heat injures the metal and destroys the mandrel. By positively gripping the metal where it encounters the strongest resistance it is fed to the mandrel positively and without slipping. At the same time, this gripping action, indenting as it does the surface of the metal, results in beneficially working or kneading the same and toughening it without injuring its fiber.

While the lines of the grooved portion of the pass are preferably nearly parallel, there is appreciable divergence inwardly from the beginning of said irregular portion, and while the divergence is not marked, still the lines are preferably such that the roll faces H do not engage the tubular blank to any appreciable extent after the latter has passed the largest diameter f of the mandrel. The result is that the engagement of the blank by the smooth portions of the rolls and by the mandrel is only sufficient to fully distend the blank, with the engagement maintained only for such distance from the termination of the irregular surfaces as to cause all of the surface depressions of the blank to disappear. With the blank thus fully distended and its surfaces smoothed the engagement is discontinued and the finished tube is subjected to no twisting and distortin strains. At the same time it emerges rom the pass fully and accurately formed and with its surfaces highly polished by the brief though effective action of the smooth portions of the rolls immediately following their indented portions.

In Fig. 3, the rounded grooves J are parallel, and in relatively close relation to each other, though the final groove K may be spaced from the other grooves, as shown. In this arrangement the gripping action is quite effective, though the kneading of the metal is not so active as with the crossed spiral grooves of Figs. 1 and 2. And with the final groove K spaced from the other grooves the metal is gripped as is necessary inwardly from the pass inlet, much of the surface irregularity being smoothed out before groove K is reached so that elimination of the irregularity formed by said groove is the principal work performed by the active smooth portions of the roll surfaces outwardly from said groove.

In Fi 4, each roll has a single spiral groove and the resulting gripping and kneading action is much the same as with the grooves of Figs. 1 and 2, though the gripping may not be so effective, nor the kneading so active.

In each of the designs, Figs. 1 to 4, the roll grooves are deepest at the pass inlet and become shallower as they approach and pass the point of the mandrel, as shown in ig. 2, so that the surface irregularities in the blank decrease in depth inwardly from the pass inlet, and less smooth rolling is necessary in the final portion of the pass than would be required if the full depth of the grooves were maintained throughout.

In the form shown in Fig. 5, the roll indentations consist of dimple-like depressions M which may be variously arranged around the rolls, but preferably in rows, with each depression merging into the adjacent depressions, and with the rows separated by a rib N which is of wave-form due to the staggerin of the depressions in the adjacent rows. epressions of this form in connection with the irregular rib separating adjacent rows cause the desirable gripping and kneading action, displacing the surface of the metal in a most effective manner without rupturing its fiber. In this adaptation the roll irregularites are located at the beginning of the active portion of the pass but do not extend backwardly over the rolls as far as in the forms first described and hence the smooth portions are of greater area. However, the metal-displacing engagement of the dimple depressions is so effective that friction-developing slipping does not occur at any point where the blank is engaged by the roll faces.

In the adaptation of Fi 6 and 7 a single frusto-conical roll P is-s own in operative relation with the faced inner periphery of the ring-like wheel Q, provided with gear teeth R for driving the same, the wheel being supported on suitable rollers S which may be mounted in any convenient frame or support, not shown. In this adaptation the inner periphery of ring Q is so surfaced as to act the same as a roll of conventional form, the action of the metal in the pass formed by the roll and ring being the same as when two rolls of like form are used. While I have illustrated this adaptation in connection with dimple-like depressions M the rolling surfaces may be variously depressed or indented.

In each of the several adaptations I prefer to rotate the mandrel along with the blank, and by preference at the same speed, thereby minimizing strains that would be set up in the metal if forced over either a fixed mandrel or a mandrel rotating oppositely to the metal.

The absence of slipping hereinbefore referred to and characterizing the operation of each of the disclosed forms of apparatus for practising the invention is due to the fact that the increase of diameter of the working faces of the rolling bodies, for instance as shown in Fig. 2, is in such exact ratio to the divergence in the same direction of the pass, and consequently in like ratio to the exterior diameter of the portion of the blank being operated upon, that nonslipping rolling contact with the metal is maintalned throughout the rolling operation. Slipping, distortion and strain resulting from roll diameter variations which are disproportionate to variations in diameter of the portion of the blank being rolled are wholly avoided. The positive gripping resulting from the irregularities in the rolling surfaces overcomes any tendency of the rolls to slip due to the resistance of the piercing mandrel, and the working or kneading of the surface of the metal resulting from such gripping improves its quality without injurin its fiber.

I c aim 1. The method of rolling tubes consisting in subjecting the metal to non-slipping rolling from the beginning to the end of the rolling operation by varying the rolling speed in proportion to diameter variations in the metal, and iercing the metal simultaneously with rol ing it.

2. The method of rolling tubes consisting in piercing a blank and thereby changing its diameter and simultaneously subjecting the metal to non-slipping rolling by varying the rolling speed in proportion to diameter variations of the metal.

3. The method of rolling tubes consisting in piercing a blank and thereby varying its diameter, subjecting the blank to non-slipping rolling by varying the rolling speed 1n proportion to diameter variations of the blank, and kneading the exterior of the blank simultaneously with rolling and piercing it.

4. The method of rolling tubes consisting in piercing a blank and thereby varying its diameter, subjecting the blank while being pierced to non-slipping rolling by varying the rolling speed in proportion to diameter variations of the blank, kneading the exterior of the blank during the first portion of the rolling operation, and smoothing the exterior thereof during the latter portion of the rolling operation.

5. The method of rolling tubes consisting in simultaneously piercing and varying the diameter of a blank, kneadin the exterior of the blank in planes in a vance of the inception of the iercing operation and in other planes whic intersect the pierced cavity, and subjecting the blank while being pierced to non-slipping rolling by varying the rolling speed in proportion to diameter variations of the blank.

6. The method of rolling tubes consisting in simultaneousl piercing and varying the diameter of a b ank, kneading the exterior of the blank in planes in advance of the inception of the piercing operation and in other planes which intersect the pierced ca ity, subjecting the blank while being pierced to non-slipping rolling by varying the rolling speed in proportion to diameter variations of the blank, and smooth rolling the kneaded blank.

In testimon whereof I afiix my signature in presence 0 two witnesses.

FRANK E. SIMPKINS.

Witnesses:

B. O. SHULMAN, ANNA BLACK. 

